But then, oh my. Pattinson, who shot to fame playing the courtly, lovestruck bloodsucker Edward Cullen, is still trying to wrap his head around where the tween-adored, carnally toothless fantasy has gone this time around.

"You spend three movies setting up the absolute, terrifying fear of sex," observed the 25-year-old English actor. "Then in this one, you have sex, and there are devastating consequences. I don't really know what it's supposed to be saying."

Whatever it is, it ain't wolf-cub love anymore. Millions have read what happens, but if you still want to be surprised, better skip the next couple of paragraphs.

Bella gets pregnant. Quick. With something that no one — not even her wise and good new vampire in-laws — can predict. They didn't even know an undead and a living person could conceive.

Whatever Bella's carrying, she wants to keep it, even though it's growing so fast and voraciously that it's clearly destroying her from within.

The movie, which opens late-night Thursday, crescendoes with perhaps the ickiest birth scene ever filmed. And it's pretty much just Pattinson and Stewart left to play the ghastly scenario out. (Taylor Lautner's werewolf Jacob, as ever, protectively lurks nearby.)

"That was the first time I've been nervous since the first movie in the series, really," said Pattinson, who still hasn't officially copped to dating Stewart for the past three years. "There was no easy way, at all, that you could hide from the reality of it. Basically, it was Kristen lying there. It was her head with this emaciated dummy; it just looked so authentic lying there, covered in blood. You just realized human beings' frailty, and there's no way not to feel that when you're looking at it.

Other than that, Pattinson appeared pleased with the emotionally, as well as physically, more mature "BD1."

"What made the first one connect with people in specific ways was that the story was so small," he observed. "There was no adventure or anything, just a small cast in a small town. And it kind of came back to that in this. It wasn't going all around the world, there was no huge army or anything.

"It was a completely personal story. And it's always more interesting to play that, especially if you're doing a fantasy movie. There's less and less to play, really, if you keep introducing characters and just having battles."

Now the question is, how will Pattinson cope with the end of the franchise that's made him a superstar? (Part 2, which was filmed simultaneously, hits theaters a year from now.) Before being cast as Edward in the 2008 movie "Twilight," the actor's main claim to fame was playing Cedric Diggory in 2005's "Harry Potter and the Goblet of Fire."

The rest of his screen credits were obscure at best. He was even seriously considering dropping acting for a music career shortly before landing the Edward gig.

In the other films he's made since 2008 — "Remember Me," "Water for Elephants," the yet-to-open "Bel Ami" — Pattinson has evinced a thirst for adult drama missing, until now, from the "Twilight" series.

And there's the just-filmed "Cosmopolis," based on a novel by literary giant Don DeLillo and directed by the very adult David Cronenberg. "It's pretty much the opposite of 'Breaking Dawn,' " said Pattinson.